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sciencehabit writes "A new study suggests that by twisting laser light, scientists could pack enough information into interplanetary beams to speed up extraterrestrial communications to the multi-gigabit level. The pulses would be passed through a hologram or multimode optical fiber, which twists the light. On the other side, a telescope would focus the light and a second hologram, or fiber would decode the signal. That could allow much more data-rich communication between, say, Earth and probes on Mars, the researchers say. Closer to home, the approach could provide Internet links of 100 gigabits per second."

But at a size like stuff like statics is on a completely different level. Imagine the stresses on such a huge networked frame during something as unseemingly as a fine-adjustment of the array's rotation. Ass ume a decade of use and these things develop into a serious factor.

I think an Lagrange point would be a better choice than the moon. The moon has too much gravity. But, as was pointed out earlier, rotating the antenna (telescope) would be a bit problem, even there. The lighter the structure, the less twist it could take.

Sounds like even someplace closer like Mars is going to take an impractically large receiver.

The Sun is roughly the same distance from Earth all the time, because we have a roughly circular orbit around it.

Mars is sometimes closer to us when our orbital position around the Sun is on the same side as Mars, however due to the different year lengths on Mars and Earth, sometimes it's much further away on the far side of the Sun to us.

cause they are not thinking about how to do it here, which is totally different than a line of site irda bullshit idea (which is fucking stupid in the first place, a laser will diffuse to be larger than the planet you want to aim for)

its a simple matter of quit wasting our time and money for these mankind space cloud ideas and lets fucking finish something down here

We need faster speeds here down on earth before we think of these "multi gigabit" speeds for interplanetary communications..

We HAVE faster speeds here on Earth. Blame your ISP for not utilizing what their network is capable of, preferring to intentionally cripple their services so they can charge through the nose for faster connections. But all that is really totally irrelevant because this Earth-Mars link is not in any way intended for consumer use.

I'm crossing my fingers. Hopefully, I'd be able to get 100G first from a martian ISP than the crappy US ISPs. And furthermore, I hope is not going to be capped by the ISP and government regulations or tapped **IA.

Bandwidth? Check. Ping? Not so much. Or rather, too much. Or something. The bandwidth being high doesn't lower the latency any of course.

"The communications delay between Earth and Mars can vary between five and twenty minutes depending upon the relative positions of the two planets. As a consequence of this, if a robot on the surface of Mars were to encounter a problem, its human controllers would not be aware of it until at least five min

Sending people to Mars does not imply large-scale long-term colonization.Serious business wouldn't be built to keep a handful of researchers connected to the homeworld. If there was sufficient demand for content, though, sure you could expect both caching much of Earth's content on Mars as well as a large cache on Earth of content from Mars.

Afaict we have 10 gigabit (maybe more now) through a single optical transciver and we can combine multiple such links on a single fiber through WDM and a typical cable contains many fibers.

The big issue with end user connections is not technical it's financial, upgrading all the connections to end users is very expensive and most users probablly aren't prepared to pay all that much more for a faster connection. So the incentive for providers to upgrade is low. Further any sensible last mile communications p

They're going to have to do something about the terrible ping times. Its orbit is about 1.5AU, so when it's close to the Earth, the round-trip ping time will be about 8 minutes. When it's on the opposite side of the sun, it'll be about 40 minutes.

Bit more than that - the sun would blind any attempts at communication when mars is directly opposite. You're going to have to either settle for being out of contact for a short time, or bounce the signal from somewhere else. The other inner planets arn't very suited to building a communication station, so probably a router at earth-sun L4/5 point.

Eight minutes means we'd have to dump this 'stream everything' internet and start actually downloading files before watching them again.

Actually, it's easier than that, just send a DVD or two to mars ever year and they'd be good to go. Plus, they can raise rates periodically because you ought to be grateful that they're letting you have all but season 3 of the Dukes of Hazard by stream.

the spins of earth and mars should present no problem just as long as we remember to unwind the cable periodically, I see no big obstacles to your idea. We can save money by only unwinding the Mars end and giving the cable a big up and down shake to undue the earth end.

I'm surprised no one has discussed TCP window size. The TCP stack on both ends will need a huge amount of RAM, and even with that, I'm not sure how they are actually going to get the throughput needed if we're talking TCP/IP.

Any high speed interplanetary connection is going to either have to put up with occasional data loss (how occasional can be influenced to some extent by forward error correction but that comes at a price in bandwidth and still doesn't really provide a soloution for block outages) or have lots of storage for retransmissions.

TCP is not appropriate, it was designed to deal with connections of relatively low latency and unknown bandwidth by slow-starting. On a high latency connection of known bandwidth that is

I'm guessing IP is out, since the latency will be horrendous. They'll probably have to bring back a mechanism like UUCP, where your files get dropped off in a temporary storage server. There, they'll be placed in a queue to be transmitted to another planet, and you'll be emailed, once transmission is complete.

There is as yet no interplanetary communication by Laser. It's all done by radio at present. The first flight demonstration [mit.edu] of Laser communication will be on the LADEE [wikipedia.org] Lunar Orbiter. That's scheduled to be launched in 2012. I am sure that optical communications will eventually be used, though. Using reasonably sized telescopes, gigabit per second communication across interplanetary distances should be possible using conventional techniques, even if OAM is not actually practical. (Of course, the weather wou

Is there that much demand for higher bandwidth, outside of earth-sats? The only machines further out than that are scientific probes, and all they need to send back is telemetry and the occasional photograph.

As I posted above, most scientific probes now are data-rate limited. They could acquire more data, but they can't send it back, due to data-rate and Earth-side antenna-availability limitations. So, yes, there is a strong demand for higher bandwidth.

But, in twenty years, when someone actually needs this stuff on Mars, you'll be looking at $0.10 GB to get it up there, even assuming NASA or the like has to pay for a special "ruggedized" harddrive that is guaranteed to work in a different atmosphere. Storage costs will drop.

I think the real problem is getting it back. Right now, probes have a really slow data connection to send back data. Assuming we can blast off tons of harddrives to them doesn't help that side of the equation.

If you want to just talk bandwidth... which is how much data can be sent from one location to another within a unit of time, then the bandwidth of a cargo van hauling a truckload of flash ram sticks across the country has, by many orders of magnitude, a higher bandwidth than any sort of technology that is built on electronic communication infrastructure.

When it becomes possible to, from earth, ping an orbiter around mars in under a second... *THEN* we will have r

Assumption fail. Volume is not necessarily a limiting constraint. Hard drives are dense.

According to this http://wiki.answers.com/Q/How_much_gravel_can_a_dump_truck_hold [answers.com] a dump truck can typically hold 13T. I've googled the weight of a 3.5" hard drive and I get values between 400g and over 1kg. So I weighed an old one, and got a bit over 400g. The 400g drives are those with fewer platters, but I'll go with it for simplicity.

100 gigabit connections will open up the vast unexplored market for molecular biology porn!On a 15 inch monitor, you'd be able to fit enough pixels to make out ribosomes and cell walls, not to mention viruses and bacteria.Pervs all over the world would devote entire discussion forums to their favorite STDs in porn stars.

of course a slashdot reader would think anything of the "molecular biology" type of sexual entertainment would involve high bandwidth and looking at a monitor. I could think of another way that involves another person.....

Isn't the limiting factor for current bandwidth power rather than speed anyways? My understanding they've long had the technology for much high bandwidth but the limitations are always power demands.

Secondary to power is usability. There's a big difference between pointing an antenna in the general direction of home and precisely aiming a laser million of miles away. Several orders of magnitude more accuracy is required.

Personally I don't find anything practical about this project. At least not today.

Picard: Mr. LaForge, we're having trouble receiving the signal from the Very Far Away Observatory. Can you boost the signal.LaForge (v.o.): Sir, we're already using a holographic multi-modal optical receiver.We're operating near the theoretical limit.Picard: Prehaps you could route secondary power through the replicators in the galley on deck 12.LaForge (v.o.): Uhm... yeah... I'll get right on that. LaForge out.

Rather than actually doing it, couldn't we just auction the interstellar bandwidth to Google, Verizon, ATT, Sprint, etc.? Then we'd close the federal deficit! Centuries from now, they'd make the money back on roaming charges. We've been passing the buck to our kids, time to exploit the great-great-great-grandkids.

Obviously, this doesn't "solve" the latency issue, but the concept does help bandwidth. Also, it doesn't replace RF links, but merely would relegate them to the failover for the IPN [wikipedia.org] version of the BGP.